Martins, CarlaEleuterio, AnaCarreiras, M. CarmoSamadi, AbdelouahidSoriano, ElenaLeon, RafaelMarco-Contelles, Jose2015-12-302015-12-302009MOLECULAR DIVERSITY. - Vol. 13, n. 4 (NOV 2009), p. 459-4681381-1991http://hdl.handle.net/10451/21387The reinvestigation of the acid-promoted cyclization of 2-(2-oxo-2-arylethyl)malononitriles, in the presence of benzylamine or aniline, in ethanol or acetonitrile, has confirmed that this is a long-time reaction process for a low-yielding synthesis of 2-amino-5-arylfuran-3-carbonitriles (2), or 2-amino-5-aryl-1-phenyl-1H-pyrrole-3-carbonitriles (4), depending on the base used. However, the microwave-assisted synthesis of 2-amino-5-(4'-methoxyphenyl)furan-3(4)-(di)carbonitriles (2c and 3c) proceeds in shorter reaction times and higher yields than does the classical thermal heating protocol. In these reactions we have observed for the first time, and characterized by their spectroscopic data and X-ray analysis, the unexpected formation of 2-amino-5-aryl-3 (4)-(di)carbonitriles (3), whose formation has been rationalized by density functional theory (DFT) analysis of the proposed reaction mechanism.. - Portuguese Foundation for Science and Technology (FCT) [SFRH/BD/17577/2004]; MEC [SAF2006-08764-C02-01]; Comunidad deMadrid [S/SAL-0275-2006]; Instituto de Salud Carlos III [RD06/0026/1002]; CSIC-GRICES project [2007PT13]. - This work was supported by the Portuguese Foundation for Science and Technology (FCT) funds as well as by C. M. Ph. D. fellowship SFRH/BD/17577/2004. M. C. C. thanks Carolina Duarte and Paula Santos for technical assistance. The present work has been supported by MEC Grants SAF2006-08764-C02-01, Comunidad deMadrid (S/SAL-0275-2006), Instituto de Salud Carlos III [Retic RENEVAS (RD06/0026/1002)], and CSIC-GRICES project (2007PT13).application/pdfengBiochemistry & Molecular BiologyChemistry, AppliedChemistry, MedicinalChemistry, Multidisciplinaryjournal articlehttp://dx.doi.org/10.1007/s11030-009-9130-3